Sorry, about the 8 wire cable post. My conversion was for a 1440GT and you have a 1340. I think the opening into the front panel on your machine is a lot larger than on the 1440. Basically, in the 1440 there is a hole through the cast material (~3/8" thick) into the control electronics enclosure. With out opening it up a larger cable would not really fit. I got two of my 8-wire and a small cable from the spindle Hall effect sensor through that hole just fine, but the original lathe cable with its thick OD insulation left little to no room for any thing else. From the images I have seen of the 1340 opening it appears to be more of a slot between to pieces of metal so would be larger? Anyway, my wires work fine for me. I needed all 16 wires for my set up.
Now with respect to your question:
As an aside, has anyone used the Analog Output from the Hitachi using the AM and L terminals (C028, code 20, Inverter Output Frequency) or Function C028, code 03, Digital Output Frequency) to monitor frequency to the motor with a remote display
I looked into this and even provided one of the 16 wires up to the front panel to measure the VFD output frequency determined via analog output voltage. Then I ask why do I need to see this frequency when I am already monitoring the RPM via the spindle its self. The real thing I wanted to know was what frequency, approximately, the VFD was going to be running out BEFORE I turned it on so that I could preset the value .... not after I turned it on. Naturally, the voltage or frequency value coming from the VFD only shows up after the VFD is running the motor so this is of little value unless you are varying the speed during operation, like in a paper mill, and want it for feed back control. So I just installed a volt meter in the front panel and connected it to the pot output. This voltage then tells me where the pot is set before I turn on the lathe. The voltage in either case is from 0-10 volts and so is only proportional to the VFD frequency not a number that equals the frequency. I also measured the voltage from the pot to the VFD to determine the frequency vs pot output. I found that the frequency was not exactly linear with the pot wiper voltage, but was close enough to give me an idea of what the resulting voltage would be. This is probably due to the VFD loading down the pot a bit as the input to the VFD is not high impedance. I then set the max frequency on the VFD to about 108 Hz. This then resulted in the voltage at the wiper pot, and so my volt meter, to be 6 volts when the frequency out of the VFD was 60 Hz. The linearity is not so bad that the volt meter reading is very far off at the lower frequencies or higher frequencies... and I seldom run the lathe anywhere near 108 Hz any way. By using a max frequency near 100 Hz the volt meter measurement in Volts is equal to the Frequency/10. So I do not have to do much of a mental conversion!
Some may express concern that the panel meters generate noise and hooking one of them up to the pot output, going directly to the VFD, might create a problem for the VFD. At least in my design I have not found this to be a problem at all. If you did then just hang a capacitor on the line to kill and noise the spikes.
Lastly, I gave a link to my conversion earlier at posting #121. At that link there are photos and documents about my conversion and the Part 2 appendix provides a list of components use in the conversion. There in those photos of the front panel, and below, you will see the three meters that I put into it along with all of the other devices. I monitor, the Spindle RPM, the VFD input voltage, and I have a spindle Revolution Counter. The counter also has an additional feature so there is a mini switch to select that mode. I posted the Excel program I used to generate the G-code to make the holes in the panel. It is linked at the conversion site. I found it especially handy when I remade the panel meter and needed to add devices and move the previous ones around. I found these RPM and counter displays, which are smaller than most, to be quite visible and readable. They work nice and cost about $14 each.... from China though so take 4 weeks to get. The design and layout is nice an neat with no EXTERNAL meters! If interested, you may want to check the operating voltages as not all meters will work on 24Vdc. I did drop the 24Vdc down to 12 via a simple 3 terminal regulator at one point. I think it may have been for one of the meters and then used on all three. A lot of these devices are made to be used in automobiles which do not usually run at 24 volts.
By the way, I think the front panel for the 1340 is almost exactly the same size as that of the 1440. It is the same width, but the 1340 may be slightly taller. I do not know the dimensions of the inside of the 1340 front panel enclosure. I think the devices that I use would also work with your conversion.
Dave L.
